This makes dylibs automatically have the correct dylib id, which means no
fixups are required.
For instance: we'd build libpinvokes.armv7.dylib from libpinvokes.armv7.m,
which by default ends up with a dylib id of "libpinvokes.armv7.dylib". With
this fix no change is required, since we now build armv7/libpinvokes.dylib
from armv7/libpinvokes.m.
Compute the dependency map for assemblies earlier, and store the results.
In a later commit we'll need to know if a dependency map was successfully
computed when determining if a task is up-to-date or not.
Rework the code that copies assemblies and their related files to the app
bundle to take into account that we might be building to frameworks now.
Also strip the assemblies when they're copied (if they must be stripped),
which removes the need for custom logic to copy files related to stripped
assemblies.
Additionally change how we handle duplicated assemblies by checking for
duplication before copying them to the app bundle. This allows us to copy
assemblies to the root directory (not the .monotouch-[32|64] subdirectory) if
the 32-bit and 64-bit versions are identical, which also means we won't need
symlinks anymore.
Make the architecture a suffix instead of infix for aotdata filenames so that
it's easier to compute the filename from the assembly name without passing
printf-style format strings around.
Create a custom AssemblyCollection class that contains a dictionary with
assembly identity (name) -> Assembly mapping.
This also means that we can detect if we end up loading multiple assemblies
with the same identity, and show an error in that case (even if that case
should never happen since we cache assemblies based on the identity, it's nice
to have code that ensures it).
Fixes: https://bugzilla.xamarin.com/show_bug.cgi?id=52238
If you give mtouch/mmp a linker xml file with bad input for
example a Xamarin.iOS app and the linker.xml has a reference
to Xamarin.Mac instead of X.I.dll i.e.
<?xml version="1.0" encoding="UTF-8" ?>
<linker>
<assembly fullname="Xamarin.Mac">
<type fullname="ObjCRuntime.Constants"/>
</assembly>
</linker>
You will get a not so helpful generic error
MT2001 Could not link assemblies. Reason: Failed to process XML description: <unspecified>
It seems that when you use a xml file for linker you get a
`XmlResolutionException` from cecil when it fails to resolve
and the better error comes from the inner exception so we use
that instead.
New error output for XmlResolutionException:
MT2017: Could not process XML description: Failed to resolve assembly: 'Xamarin.Mac, Culture=neutral, PublicKeyToken=null'
Resource files for mac should be copied to the app bundle
* Move the Satellite code used by mac to tools/common/Assembly.cs
* Add EmbeddedResources test to xammac_tests
Most projects building to bitcode (any kind of bitcode, this includes the
marker-only version as well), will fail to link when linking with third-party
libraries and incremental builds are enabled.
So automatically disable incremental builds when we detect this scenario.
This is only a workaround until we can make this scenario build correctly.
https://bugzilla.xamarin.com/show_bug.cgi?id=51710
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.
According to Vlad it's not necessary to set MONO_GC_PARAMS during AOT-
compilation, since all MONO_GC_PARAMS options can be changed at runtime:
Rolf Kvinge [16:35] @vlad.brezae is this true for all the different options MONO_GC_PARAMS take: https://github.com/xamarin/xamarin-macios/pull/1546#discussion_r97318092?
Rolf Kvinge [16:36] I remember this: https://bugzilla.xamarin.com/show_bug.cgi?id=35414#c14
Rofl Kvinge [16:36] which apparently you changed here, so that it can be changed at runtime: https://bugzilla.xamarin.com/show_bug.cgi?id=35414#c27
Rolf Kvinge [16:36] but I don't know if this is true for all the options you can pass using MONO_GC_PARAMS
Vlad Brezae [16:41] yes, it should be true for all of them, that was a bug
Rolf Kvinge [16:41] ok, that's great news 😄
Performance tests
-----------------
This is for a new watchOS extension project, built for release.
* The default (currently -O2) optimizations: 41s ( baseline ) 30.027.060 bytes ( baseline )
* All optimizations disabled (`--llvm-opt=all=`): 17s (-24s = -59%) 32.978.312 bytes (+2.951.252 = +10%)
* Optimized for size (`--llvm-opt=all=-Os`): 36s ( -5s = -12%) 28.617.408 bytes (-1.409.652 = -5%)
* Optimized for more size (`--llvm-opt=all=-Oz`): 35s ( -6s = -15%) 28.601.016 bytes (-1.426.044 = -5%)
* Optimized slightly (`--llvm-opt=all=-O1`): 35s ( -6s = -15%) 28.666.556 bytes (-1.360.504 = -5%)
* Optimized a lot (`--llvm-opt=all=-O3`): 41s ( 0s = 0%) 30.403.996 bytes (+ 376.936 = +1%)
Conclusions
-----------
* The fastest build by far (less than twice as fast) is if optimizations are
disabled, but this adds a 10% size penalty (~3 MB in this test case),
compared to the baseline, and 15% size penalty (4.3 MB) compared to -Oz.
* -Oz seems to have the best overall results: at least as fast as any other
optimized build, and the smallest app as well.
Caveats
-------
Some optimizations might not work the AOT compiled code. The resulting
binaries have not been tested.
Event sequence:
* mtouch is executed with the linker disabled.
* The linker pipeline copies all input assemblies (since the linker is
disabled the assemblies don't change) into the PreBuild directory. This will
keep the original timestamps of the input assemblies.
* mtouch is executed again, when none of the input assemblies changed.
* The linker pipeline will re-execute, because it will see that at least one
of the input assemblies (at least the .exe) is newer than at least one of
the assemblies in the PreBuild directory (usually a framework assembly,
because those have the original timestamp from their install location).
Fix:
Touch all the assemblies in the PreBuild directory after the linker pipeline
executes the first time. This way the second time mtouch is executed, it will
find that all assemblies in the PreBuild directory have timestamps later than
all the input assemblies, so it will load the cached linked assemblies,
instead of re-executing the linker pipeline.
Switch to a new API introduced in Cecil added new API to get all the
attributes in an assembly, without having to traverse (and load) every type
and member.
This makes mtouch significantly faster when computing the list of referenced
assemblies, which is noticable when mtouch later determines nothing else needs
to be done (because nothing changed).
A few tests show that mtouch is now approximately twice as fast:
* A customer test project goes from 2s to 1s.
* A simple test app goes from 1.3s to 0.6.
https://bugzilla.xamarin.com/show_bug.cgi?id=49087
The native linker treats object files (.o) and static libraries (.a files,
which are archives of .o files) differently.
The native linker will always include object files into the executable:
$ echo "void xxx () {}" > foo.m
$ clang -c foo.m -o foo.o -arch x86_64
$ ld foo.o -dylib -o foo.dylib -macosx_version_min 10.12 -arch x86_64
$ nm foo.dylib
0000000000000fe0 T _xxx
However, if the object file is inside a static library:
$ echo "void xxx () {}" > foo.m
$ clang -c foo.m -o foo.o -arch x86_64
$ ar cru foo.a foo.o
$ ld foo.a -dylib -o foo.dylib -macosx_version_min 10.12 -arch x86_64
$ nm foo.dylib
<no output>
This means that our testing library (libtest.a) which is a fat library of
_object files_, do not show the problems reported in bug #51548.
So:
a) I've fixed the creation of libtest.a to be a fat library of _static
libraries_. This causes the `FastDev_LinkWithTest` test to fail exactly
like in bug #51548.
b) I've made mtouch pass `-u <native symbol>` to the native linker, for every
native symbol referenced in a managed assembly, when creating a dylib.
Amazingly this seems to work fine even with symbols to Objective-C classes
(`_OBJC_CLASS_$_<class name>`).
c) This also required adding support for collecting the Objective-C names of
all managed types registered with Objective-C to the linker. The
information is already available in the static registrar, but that would
require us to make sure the static registrar is executed before compiling
dylibs, which means those two tasks won't be able to run in parallel (also
there's no guarantee we'll even run the static registrar).
https://bugzilla.xamarin.com/show_bug.cgi?id=51548
TL&DR: This is *how* it should be done and tested, it's not complete
(single, simple case) nor the most interesting case ;-)
The trick is to make sure each case is covered by tests so a mono
_bump_ won't give us a BCL that does not conform to what the linker
expect.
What's the impact ?
1. There is the expected reduction of metadata in mscorlib. Since both
methods don't call other API there's no indirect effect (removal).
--- before 2017-01-15 11:12:44.000000000 -0500
+++ after 2017-01-15 11:12:56.000000000 -0500
@@ -13166,9 +13166,6 @@
System.Void System.Security.SecurityException::.ctor(System.Runtime.Serialization.SerializationInfo,System.Runtime.Serialization.StreamingContext)
System.Void System.Security.SecurityException::.ctor(System.String)
System.Void System.Security.SecurityException::GetObjectData(System.Runtime.Serialization.SerializationInfo,System.Runtime.Serialization.StreamingContext)
-System.Boolean System.Security.SecurityManager::CheckElevatedPermissions()
-System.Security.SecurityManager
-System.Void System.Security.SecurityManager::EnsureElevatedPermissions()
System.Security.SecurityRulesAttribute
System.Security.SecurityRuleSet System.Security.SecurityRulesAttribute::m_ruleSet
System.Void System.Security.SecurityRulesAttribute::.ctor(System.Security.SecurityRuleSet)
2. There is no visible size change (even with #1) in mscorlib.dll due to
padding (compiler /filealign)
mscorlib.dll 793,600 793,600 0 0.00 %
3. there's a *very* small reduction of mscorlib.*.aotdata size
mscorlib.armv7.aotdata 717,264 717,216 -48 -0.01 %
mscorlib.arm64.aotdata 712,840 712,704 -136 -0.02 %
AOT data *.aotdata 6,460,064 6,459,880 -184 0.00 %
4. there's no change in executable size - normal as the AOT compiler has
_likely_ already doing the same optimization (before this commit)
Executable 29,270,272 29,270,272 0 0.00 %
Full comparison: https://gist.github.com/spouliot/0464c8fa3a92b6486dfd90595d9eb718
We're not storing selectors in fields anymore so this step does nothing
expect iterating over the code.
The step is still needed for `mmp` (for Xamarin.Mac.dll)
This allows mtouch to give better error message when something unexpected
occurs in the linker pipeline (at least for the sub-steps).
Practically it means fewer, contextless MT2001 errors. The replacements
error code are more precise, e.g.
* what was being done;
* what was being processed
and helps both diagnosing and, possibly, gives clues for workarounds
Build extensions and the container app in the same mtouch process, by storing
all the mtouch arguments when called to build extensions in a text file, and
then reloading those arguments when called to build the main app.
This is required if we want to share code between extensions and the
container.
Rolf Bjarne Kvinge
Alex Soto
Timothy Risi
Vlad Brezae
Sebastien Pouliot