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Codeon Gmbh


This is an Objective-C compiler based on clang 10.0.0, written for the mulle-objc runtime. It corresponds to mulle-objc-runtime v0.17 or better.

See README.txt for more information about clang

The compiler can be used to:

  1. compile Objective-C code for mulle-objc
  2. compile C code

It is not recommended to use it for C++, since that is not tested. It is not recommended to use it for other Objective-C runtimes, since there have been some changes, that affect other runtimes.


The compiler compiles Objective-C source for the mulle-objc runtime by default. When compiling for mulle-objc the compiler will use the meta-ABI for all method calls. The resultant .o files are linkable like any other compiled C code.

AAM - Always Autorelease Mode

The compiler has a special mode called AAM. This changes the Objective-C language in the following ways:

  1. There is a tranformation done on selector names

    Name Transformed Name
    alloc instantiate
    new instantiatedObject
    copy immutableInstance
    mutableCopy mutableInstance
  2. You can not access instance variables directly, but must use properties (or methods)

  3. You can not do explicit memory management (like -dealloc, -autorelease, -release, -retain, -retainCount etc.)

The transformed methods will return objects that are autoreleased. Hence the name of the mode. The net effect is, that you have a mode that is ARC-like, yet understandable and much simpler.

Your ARC code may not run in AAM, but AAM code should run in ARC with no problems. If you can't do something in AAM, put it in a category in regular Objective-C style.

The compiler handles .aam files, which enables AAM ("Always Autoreleased Mode").

Additional Compiler options and defined macros

Name Compiler Default Description
__MULLE_OBJC__ - - Compiling for mulle-objc
__MULLE_OBJC_UNIVERSEID__ -fobjc-universename=name - id of the universe, or 0 for default universe
__MULLE_OBJC_UNIVERSENAME__ -fobjc-universename=name - name of the universe, or NULL for default universe

The following table represents option pairs, that logically exclude each other. Either one is always defined.

Name Compiler Default Description
__MULLE_OBJC_AAM__ .aam file - AAM is enabled
__MULLE_OBJC_NO_AAM__ .m file - AAM is not enabled
Β  Β  Β 
__MULLE_OBJC_TPS__ -fobjc-tps YES TPS (tagged pointer support) is enabled
__MULLE_OBJC_NO_TPS__ -fno-objc-tps NO TPS is not enabled
Β  Β  Β 
__MULLE_OBJC_FCS__ -fobjc-fcs YES FCS fast method/class support is enabled
__MULLE_OBJC_NO_FCS__ -fno-objc-fcs NO FCS is not enabled

Macros used in Code Generation

The compiler output can be tweaked with the following preprocessor macros. All macros must be defined with a simple integer, no expressions. All of them are optional, unless indicated otherwise. The runtime, the Objective-C Foundation on top of the runtime and the user application, will define them.

Name Description
MULLE_OBJC_RUNTIME_VERSION_MAJOR Major version of the runtime
MULLE_OBJC_RUNTIME_VERSION_MINOR Minor version of the runtime
MULLE_OBJC_RUNTIME_VERSION_PATCH Patch version of the runtime
MULLE_OBJC_FOUNDATION_VERSION_MAJOR Major version of the Foundation
MULLE_OBJC_FOUNDATION_VERSION_MINOR Minor version of the Foundation
MULLE_OBJC_FOUNDATION_VERSION_PATCH Patch version of the Foundation
MULLE_OBJC_USER_VERSION_MINOR User supplied of the Foundation
MULLE_OBJC_USER_VERSION_PATCH User supplied of the Foundation, all these version information values will be stored in the emitted object file.
MULLE_OBJC_FASTCLASSHASH_0 First unique ID of a fast class
... ...
MULLE_OBJC_FASTCLASSHASH_63 Last unique ID of a fast class

Functions used in Code Generation

These are the runtime functions used for method calling, retain/release management, class lookup and exception handling. They are defined in the runtime.


Function Memo
mulle_objc_exception_tryenter @throw
mulle_objc_exception_tryexit @finally
mulle_objc_exception_extract @catch
mulle_objc_exception_match @catch

-O0, -Os

Function Memo
mulle_objc_object_call [self foo:bar]
_mulle_objc_object_supercall [super foo:bar]
mulle_objc_object_lookup_infraclass_nofail [Foo ... for methods
mulle_objc_object_lookup_infraclass_nofast_nofail __MULLE_OBJC_NO_FCS__
mulle_objc_global_lookup_infraclass_nofail [Foo ... for functions
mulle_objc_global_lookup_infraclass_nofast_nofail __MULLE_OBJC_NO_FCS__


Like -O0, but two functions are replaced:

Function Memo
mulle_objc_object_partialinlinecall [self foo:bar]
_mulle_objc_object_partialinlinesupercall [super foo:bar]


Like -O1, but four functions are replaced with two, and two new functions are used:

Function Memo
mulle_objc_object_inlinelookup_infraclass_nofail [Foo ... for both FCS modes
mulle_objc_global_inlinelookup_infraclass_nofail [Foo ... for both FCS modes
mulle_objc_object_inlineretain [foo retain]
mulle_objc_object_inlinerelease [foo release]


Like -O3, but two functions are replaced:

Function Memo
mulle_objc_object_inlinecall [self foo:bar]
_mulle_objc_object_inlinesupercall [super foo:bar]



You can use homebrew to install the compiler (only):

brew install codeon-gmbh/software/mulle-clang

If for some reason homebrew can not use the bottle, the compiler must be built from source. This takes a long time! On my Macbook Air the build can take an hour or more.


You can install mulle-clang with mulle-lldb via apt-get on Ubuntu:

sudo apt-get update &&
sudo apt-get install curl

curl -sS | sudo apt-key add -
echo "deb [arch=all] `lsb_release -c -s` main" | sudo tee "/etc/apt/sources.list.d/" > /dev/null

sudo apt-get update &&
sudo apt-get install mulle-clang


You can install on Debian (and Ubuntu) with dpkg after downloading the appropriate package. Notice that the packages are still named with Ubuntu codes.

sudo dpkg --install mulle-clang-${Ubuntu}-amd64.deb
Debian Ubuntu shasum -b -a 256
bullseye focal 7305622a81ae3d2579f32622ef40e6fdd38d068fa717e4adf60b5ea9b98e6559
buster bionic 3d54a5398d4f3884372094199fea7f4e99c5aea9c0bd066009d855685623b97e
stretch xenial e0cfb43302cf9073786590f663a38e304b0350fe11e9f07b1cfd04bab23a56e9
stretch i386 xenial i386 86df0d2fbe578514b7f42344c24a7884d5c667b5a7731fb8a15bf4dbd5e8b761


Afterwards head on over to mulle-objc to get the runtime libraries.


Nat! for Codeon GmbH