Could you expand on this more? I don't know a lot about GUI programming, but I'd be interested in learning what the current failings are within the desktop space.
Instead, developers rely on toolkits such as Qt or GTK to ensure compatibility, which are usually either bloated or ugly.
IIRC the fancier toolkits (Qt, GTK) do widget accell with either mandatory blitting and/or 3d (OpenGL/DirectX) (Other frameworks like WPF and Cocoa are notorious for this too).
There are, or used to be, frameworks that were not gpu dependent.
I've never hear nor seen these massive drops you claim to, so either you are running 20 year old hardware or your graphics aren't on, or you have some other hardware issue...
When I said "I don't understand the technical reasons behind it", I didn't mean "I don't understand how to abstract OS-native APIs". I meant "I don't understand how a team of intelligent people managed to fuck things up this badly".
Get your favourite Qt program, resize the window like a madman and watch your CPU usage launch into the stratosphere.
You’d probably also want some form of malloc(), but that’s completely optional. There’s nothing in Objective C that says you have to allocate memory dynamically, or that you have to do it with malloc.
ObjC runtime has grown somewhat to include more features, but you don’t need all those runtime features if you want to run your code on a microcontroller. Just like you don’t need glibc if you want to run C. There is more than one runtime for Objective C you can choose, just like there is more than one runtime for C.
You can have all the 'simple' calls you like but if you need to malloc half a gig of ram just to get started...that is heavy and bloated.
Also you say 'architecture' but unless you are talking a battery hungry cellphone you are probably talking 16 or 32 bit proc not 64, which means potentially massive increase in the size of code to be generated since you lose certain instruction sets. I don't know realistically what Obj C uses in the osx cpu architecture but I'm almost certain it's not going to be as simple as just retargeting your compiler...
Not saying it can't be done but take even the new arm laptops from Apple - that's a significant hardware investment on top of a bunch of software tricks, not just a casual retargetting that can be portably moved to other low power systems.
Objective C is in mainline GCC. You retarget your compiler and port the runtime. As far as I know, any target with GCC support can run Objective C, given a runtime. The important parts of the runtime require kilobytes, not megabytes, of space.
Remember that Objective C was originally a very thin layer on top of C. You take all the [method calls] and replace them with calls to objc_msgSend(). The overhead is fairly small— your object instances need the “isa” pointer, which is basically just a pointer to a vtable. The objc_msgSend() function reads the vtable and forwards method calls to the correct implementation.
My experience is that Objective C binaries typically have a much smaller footprint than C++ binaries. That’s obviously not some kind of rule, but it reflects idiomatic usage of Objective C. In C++ you'd use a std::vector<T> which is a templated class, which gets instantiated for every different T you use in your program. In Objective C, you’d use NSArray, which is monomorphic.
This all should be completely unsurprising—since Objective C first appeared in the 1980s, it’s no surprise that it doesn’t need much memory.
It's definitely a lot more than the NeXT days. GCC got fast enumeration, exceptions, garbage collection (if you really want it), synthesized properties, etc. These are the "Objective C 2.0" features which got released in 2007, back before Apple was shipping Clang.
GCC doesn't have ARC, array / dictionary literals, or other new features. But it's definitely a lot more than Objective C from the NeXT days. These are "modern" Objective C. They're also basically just sugar for the appropriate calls to +[NSArray arrayWithObjects:...] or -[retain] / -[release] etc.
Debating whether some language feature can exist on an mcu is somewhat unrelated - the point was about code size bloat not whether you can fake one instruction set with another...
You can fake e.g. multiply with a for loop and an add instruction (1 or 2 cycles) but that will run orders of magnitude slower than a 2 or 3 clock cycle multiply instruction...
So the point about osx arch is not really addressed, if you have runtime that cannot be easily ported or osx cpu arch which produces prohibitive instruction sets it doesn't matter if gcc can target an old version of objective C, it is, as stated, not that simple.