Dalija Prasnikar

@Sherlock If you get warnings, then this is kind of code that needs to be changed for ARC. But the change you do (depending on the actual code you need to change) will work across all compilers without warnings.

52 minutes ago, Richard_Stevens said:

Thumbs up from me. We have a couple of VCL products that make heavy use of relatively complex, object-based libraries that we debated moving onto mobile - but were put off by the rats nest of potential issues and number of IFDEFS it would have needed. If in 12-18 months' time we can re-use those libraries more or less "as is" then that will be great.

Just for the record, unless you have to change methods signatures - adding const param, and for some reason you need to keep old signature too, porting to ARC compiler itself does not require any IFDEFS. 

All needed changes are compatible with all compilers.

I found the report for Linux compiler that may have some impact on speed comparing to Windows (regardless of ARC)

Linux x64 compiler produce very bloated code

2 hours ago, Lars Fosdal said:

I welcomed ARC in principle, but there were three key problems for me:
1. Having two different memory management models in our code base was not an option
2. ARC carried an unexpectedly high performance penalty 
3. The pitfalls of ARC were as many and as complex as for the classic reference count problems.

1. Totally understandable. You cannot use ARC to its full potential and you are only paying the price.

2. I assume it was Linux vs Windows,

It would be interesting to see how it compares with ARC removed. Comparing x86 with ARM is comparing apples with oranges - ARC or no ARC. AFAIK, LLVM backend has some influence on performance, too. There are some reports about inefficient code generation - something not ARC related. 

Performance mostly suffers because of existing code that is not written for ARC - unnecessary reference counting triggers are real performance killers. It is not fault of ARC per-se.  

3. LOL - it is the same memory management model, (if you remove DisposeOf out of the picture) so pitfalls are exactly the same. Developing for ARC requires a bit different mindset.

4 hours ago, Marco Cantu said:

Honestly interested in feedback, suggestions and ideas. Less in "I told you" comments... 

I think most of EMBT customers will see that as a positive move. While I fully understand them, I am not so sure.

More thoughts... ARC is dead, long live ARC