6 ms·

Apple will "take at least several months" to release LLVM backend for 64-bit A7

53 points by yapcguy 13y ago

ianstallings 13y ago
Must be a significant fork and/or the code is not "pretty". No one wants to embarrass themselves and they probably have to peer review it, etc. All with managers breathing down their necks :D
- general_failure 13y ago
  I guess they kept it secret because no-one has a 64-bit embedded cpu.
  - kps 13y ago
    It seems obvious that they kept it secret because if Apple had been pushing out improvements to the ARM64 code generator for the past months, someone would have connected the dots and understood they were building an ARM64 device. All Chris Lattner's message is saying is that Apple's contributions here are subject to the same process as anyone else, namely incremental commits with community review.
    - AnthonyMouse 13y ago
      >It seems obvious that they kept it secret because if Apple had been pushing out improvements to the ARM64 code generator for the past months, someone would have connected the dots and understood they were building an ARM64 device. Existing high end mobile devices have on the order of 2GB of memory. It doesn't take a genius to work out that they're soon going to have 4GB or more and hit the ceiling of a 32-bit address space. Why bother keeping a secret something the entire market already knows is going to happen in short order?
      - derefr 13y ago
        Because the timing between "when that information comes out" and "when apple have something to show that people can buy" greatly affects their stock price.
    - ianstallings 13y ago
      What they might have done instead is reached out to the core team and let them in on it up front. Now it's going to be one huge code review after they commit their changes.
      - kps 13y ago
        We don't know that they didn't; it takes about 5 seconds of 'git log lib/Target/AArch64' to see that it hasn't exactly been wild with activity this summer. Again, the point of the message is that it isn't going to be 'one huge code review', it's going to be incremental small reviews, same as anyone else's contributions. I have plenty of gripes with Apple (half of which can be inferred from the fact I'm personally running 10.6.8 for the foreseeable future) but this isn't one of them.
threeseed 13y ago
Nothing to see here. There is an existing implementation, Apple's implementation and hence it will take at least several months to merge the two, legal sign off and then committed.
- yapcguy 13y ago
  In the mean-time, the community will be wasting time and effort in trying to solve ARM 64-bit issues which Apple has already solved. If LLVM were under a copyleft license like the GPL, Apple could still have created it's backend in secret to time its release with the new iPhone. BSD style licenses leave the community at the mercy of corporate interests. If Apple decides not to release[1] its backend, too bad, and we all play catch-up. [1] "We're going to the standards bodies, starting tomorrow, and we're going to make FaceTime an open industry standard." Steve Jobs
  - klodolph 13y ago
    We already have a copyleft compiler, GCC, and under the stewardship of the FSF it has turned into a total mess. The community has been wasting effort for years duplicating issues that have already been solved in GCC because the FSF refused to merge patches that would make it modular. On the other hand, you can download Clang and make your own tools from it now. Go ahead, I dare you to do either of the following: * Use GCC's C frontend to write a code analysis tool of any sort, * Write a new frontend to GCC. FSF's damage to the GCC code base proved that you can still sabotage freedom while adhering to the letter of a copyleft license. I suspect the KHTML mess is still fresh in the minds of many engineers at Apple.
    - LukeShu 13y ago
      Since 1999, GCC has been under the stewardship of the GCC steering committee[1], not the FSF. [1]: http://gcc.gnu.org/steering.html http://gcc.gnu.org/steering.html
  - eridius 13y ago
    > If LLVM were under a copyleft license like the GPL, ... You say that as if making such a dramatic license change would affect nothing else besides the rate at which changes made by companies get released to the wild. That's preposterous. If LLVM were GPL'd then Apple would not be using it. Full stop.
maxharris 13y ago
Kudos to Apple for doing the right thing. It is within Apple's rights to not release the code at all. Or they could have just dumped what they had, warts and all, leaving the mess for other maintainers to sort out. Or they could have plugged away silently, getting ready for a release without notifying anyone (which would have resulted in unnecessary duplication of effort - think Linux on IBM mainframes). What they've done here is the most respectful and responsible thing possible.
- ajross 13y ago
  I'm reading this over and over and still not understanding how withholding source code is "the right thing" and worthy of praise. Either it's an open source toolchain or it's not. Apple's iOS compiler isn't. There's no particular shock there -- the platform it targets certainly isn't open either. We don't freak out when MSVC is released without source. But we don't praise Microsoft either. Maybe it will be open source some day. If it is, then is the appropriate time to deliver "kudos" -- certainly not now.
  - kps 13y ago
    > Either it's an open source toolchain or it's not. LLVM is an open source toolchain. Not every project built on LLVM is an open source toolchain. For copyleft ideologues this is a problem. Not everyone is a copyleft ideologue.
  - mcphage 13y ago
    > I'm reading this over and over and still not understanding how withholding source code is "the right thing" and worthy of praise Because the other option is to do a code-dump of their customized code, making it nearly impossible to merge back into the main trunk. They've done that before, and gotten bitched out about it (and rightfully so). Doing it this way shows that their goal is to move the project forward by adding their new contributions, not merely fulfilling their legal obligation to "get it out there", regardless of whether the main project gets any benefit.
    - x0x0 13y ago
blahbl4hblah 13y ago
The NSA is probably making them do it... also NSA, NSA, and NSA.
gdonelli 13y ago
Reminds me when Darwin (Leopard days) went to x86 and the sources of Darwin were stale for a very long time
jnbiche 13y ago
I'm not the biggest Apple fan around, but if this is meant to be some kind of expose of wrongdoing, I completely disagree. First, under the BSD, they're under no obligation to do anything with their improvements to LLVM, which is exactly how supporters of permissive licenses (like me) like it, even though we often also encourage users to contribute back if they can. Second, although they're under no obligation to contribute back, they're going to do so anyway, because they 1) understand that this is probably in their best interest, and 2) presumably want to help support and foster the LLVM community. Merging in all this code -- necessarily done in private since it was a confidential company project -- is likely a major undertaking, so they want to be sure to get it right. And yet they're giving the LLVM community heads-up not to spend time working on that particular solved problem. All in all, nothing to see here.
- azakai 13y ago
  > I'm not the biggest Apple fan around, but if this is meant to be some kind of expose of wrongdoing, I completely disagree. Why would you think it is such a thing?
  - firat 13y ago
    Have you read past the first sentence?

53 points by yapcguy 13y ago

Must be a significant fork and/or the code is not "pretty". No one wants to embarrass themselves and they probably have to peer review it, etc. All with managers breathing down their necks :D

general_failure 13y ago
I guess they kept it secret because no-one has a 64-bit embedded cpu.
- kps 13y ago
  It seems obvious that they kept it secret because if Apple had been pushing out improvements to the ARM64 code generator for the past months, someone would have connected the dots and understood they were building an ARM64 device. All Chris Lattner's message is saying is that Apple's contributions here are subject to the same process as anyone else, namely incremental commits with community review.
  - AnthonyMouse 13y ago
    >It seems obvious that they kept it secret because if Apple had been pushing out improvements to the ARM64 code generator for the past months, someone would have connected the dots and understood they were building an ARM64 device. Existing high end mobile devices have on the order of 2GB of memory. It doesn't take a genius to work out that they're soon going to have 4GB or more and hit the ceiling of a 32-bit address space. Why bother keeping a secret something the entire market already knows is going to happen in short order?
    - derefr 13y ago
      Because the timing between "when that information comes out" and "when apple have something to show that people can buy" greatly affects their stock price.
  - ianstallings 13y ago
    What they might have done instead is reached out to the core team and let them in on it up front. Now it's going to be one huge code review after they commit their changes.
    - kps 13y ago
      We don't know that they didn't; it takes about 5 seconds of 'git log lib/Target/AArch64' to see that it hasn't exactly been wild with activity this summer. Again, the point of the message is that it isn't going to be 'one huge code review', it's going to be incremental small reviews, same as anyone else's contributions. I have plenty of gripes with Apple (half of which can be inferred from the fact I'm personally running 10.6.8 for the foreseeable future) but this isn't one of them.

threeseed 13y ago

Nothing to see here. There is an existing implementation, Apple's implementation and hence it will take at least several months to merge the two, legal sign off and then committed.

yapcguy 13y ago
In the mean-time, the community will be wasting time and effort in trying to solve ARM 64-bit issues which Apple has already solved. If LLVM were under a copyleft license like the GPL, Apple could still have created it's backend in secret to time its release with the new iPhone. BSD style licenses leave the community at the mercy of corporate interests. If Apple decides not to release[1] its backend, too bad, and we all play catch-up. [1] "We're going to the standards bodies, starting tomorrow, and we're going to make FaceTime an open industry standard." Steve Jobs
- klodolph 13y ago
  We already have a copyleft compiler, GCC, and under the stewardship of the FSF it has turned into a total mess. The community has been wasting effort for years duplicating issues that have already been solved in GCC because the FSF refused to merge patches that would make it modular. On the other hand, you can download Clang and make your own tools from it now. Go ahead, I dare you to do either of the following: * Use GCC's C frontend to write a code analysis tool of any sort, * Write a new frontend to GCC. FSF's damage to the GCC code base proved that you can still sabotage freedom while adhering to the letter of a copyleft license. I suspect the KHTML mess is still fresh in the minds of many engineers at Apple.
  - LukeShu 13y ago
    Since 1999, GCC has been under the stewardship of the GCC steering committee[1], not the FSF. [1]: http://gcc.gnu.org/steering.html http://gcc.gnu.org/steering.html
- eridius 13y ago
  > If LLVM were under a copyleft license like the GPL, ... You say that as if making such a dramatic license change would affect nothing else besides the rate at which changes made by companies get released to the wild. That's preposterous. If LLVM were GPL'd then Apple would not be using it. Full stop.

maxharris 13y ago

Kudos to Apple for doing the right thing. It is within Apple's rights to not release the code at all. Or they could have just dumped what they had, warts and all, leaving the mess for other maintainers to sort out. Or they could have plugged away silently, getting ready for a release without notifying anyone (which would have resulted in unnecessary duplication of effort - think Linux on IBM mainframes). What they've done here is the most respectful and responsible thing possible.

ajross 13y ago
I'm reading this over and over and still not understanding how withholding source code is "the right thing" and worthy of praise. Either it's an open source toolchain or it's not. Apple's iOS compiler isn't. There's no particular shock there -- the platform it targets certainly isn't open either. We don't freak out when MSVC is released without source. But we don't praise Microsoft either. Maybe it will be open source some day. If it is, then is the appropriate time to deliver "kudos" -- certainly not now.
- kps 13y ago
  > Either it's an open source toolchain or it's not. LLVM is an open source toolchain. Not every project built on LLVM is an open source toolchain. For copyleft ideologues this is a problem. Not everyone is a copyleft ideologue.
- mcphage 13y ago
  > I'm reading this over and over and still not understanding how withholding source code is "the right thing" and worthy of praise Because the other option is to do a code-dump of their customized code, making it nearly impossible to merge back into the main trunk. They've done that before, and gotten bitched out about it (and rightfully so). Doing it this way shows that their goal is to move the project forward by adding their new contributions, not merely fulfilling their legal obligation to "get it out there", regardless of whether the main project gets any benefit.
  - x0x0 13y ago

blahbl4hblah 13y ago

The NSA is probably making them do it... also NSA, NSA, and NSA.

gdonelli 13y ago

Reminds me when Darwin (Leopard days) went to x86 and the sources of Darwin were stale for a very long time

jnbiche 13y ago

I'm not the biggest Apple fan around, but if this is meant to be some kind of expose of wrongdoing, I completely disagree. First, under the BSD, they're under no obligation to do anything with their improvements to LLVM, which is exactly how supporters of permissive licenses (like me) like it, even though we often also encourage users to contribute back if they can. Second, although they're under no obligation to contribute back, they're going to do so anyway, because they 1) understand that this is probably in their best interest, and 2) presumably want to help support and foster the LLVM community. Merging in all this code -- necessarily done in private since it was a confidential company project -- is likely a major undertaking, so they want to be sure to get it right. And yet they're giving the LLVM community heads-up not to spend time working on that particular solved problem. All in all, nothing to see here.

azakai 13y ago
> I'm not the biggest Apple fan around, but if this is meant to be some kind of expose of wrongdoing, I completely disagree. Why would you think it is such a thing?
- firat 13y ago
  Have you read past the first sentence?