compiling for the ipad

Project Infrastructure LLVM Dev List Archives
1

Hi

I have been assigned the task of porting the ARM code generator to the ipad.

I would like to know if there are any available documents about the instruction set/code format of the A64 chip of Apple.

Also, if at all possible, documents that describe executable formats, etc are welcome.

Any pointers?

Thanks in advance.

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Weird. The xcode compiler has been llvm for a long time, and A64 has been supported since the iPhone 5s came out four years ago.

Perhaps you’re asking this because you have an existing project targeting A32 and Apple just made that obsolete.

I wouldn’t advise starting a project doing specifically native compilation for iPhone or iPad at this point. New iOS projects have defaulted to uploading llvm bitcode to the iTunes store for about two years already. It’s still possible to change this (or use old projects) right now, but I would not be surprised if bitcode-only becomes compulsory very soon, the same as WatchOS and tvOS are already.

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Weird. The xcode compiler has been llvm for a long time, and A64 has been
supported since the iPhone 5s came out four years ago.

Perhaps you're asking this because you have an existing project targeting
A32 and Apple just made that obsolete.

This is part of a larger project.
The code generator is a part of a database system, written in C++. This
system compiles each sql statement into C code that is written into a text
buffer. The code generator reads this buffer, compiles into assembly code
and executes it "on the fly".

And .. why do you think you'll be able to do this? iOS has always forbidden
on the fly code generation. You can't mprotect() memory to executable (and
it can't be executable and writable at the same time).

Now, I need to know the opcodes and specifications of the A 64 chip.

I wouldn't advise starting a project doing specifically native compilation
for iPhone or iPad at this point. New iOS projects have defaulted to
uploading llvm bitcode to the iTunes store for about two years already.
It's still possible to change this (or use old projects) right now, but I
would not be surprised if bitcode-only becomes compulsory very soon, the
same as WatchOS and tvOS are already

We are not going to use the App store. Our customers will get our product
from us.
Of course we will use Xcode, since we already did the port to Mac OS X.

Again my question: Is there any documentation about the A64?

Arm64 is well documented in the usual place

https://static.docs.arm.com/ddi0487/b/DDI0487B_a_armv8_arm.pdf