7 ms·

One thing I don't understand about Swift is why it uses a private fork of LLVM. Why can't they upstream whatever changes they need?

pjmlp 2y ago
Because the same also applies to clang, and contrary to what people think, Apple like every other big tech, is only as nice to FOSS as they need to be for their own purposes. Same applies to all C and C++ compiler vendors, that have replaced their proprietary compilers (there are plenty more than just clang/gcc/msvc), with LLVM. Such is the freedom of Apache/MIT/BSD style licenses.
- peppermint_gum 2y ago
  Swift's LLVM fork is open-source, just not upstreamed. No Free Software license requires forks to upstream their changes. https://github.com/swiftlang/llvm-project https://github.com/swiftlang/llvm-project
  - pjmlp 2y ago
    Yet you're complaining that they are using the licence exactly as they feel like.
    - nequo 2y ago
      Parent was not complaining. Parent was asking what the rationale is behind maintaining a separate LLVM fork instead of upstreaming and reducing the maintenance burden on Apple engineers.
  - Zambyte 2y ago
    Referring to their fork as "private" seems quite misleading then.
- okr 2y ago
  I would not say its about niceness, its more about necessities. If ya don't own something, the walls are high to have anything changed, naturally. Because it might not be aligned with what the owner has had in it's mind. And you want to move quickly. So you fork and apply your changes. But i also think, in the long run, it hurts, bcs at some point, you forks are too diverged. But so is life.
ezfe 2y ago
I’ve just read the swift build guide and there’s no sign of a closed-source version of LLVM. What are you talking about?
- mkl 2y ago
  peppermint_gum didn't mention a closed-source version of LLVM either. "Private" just means "their own" here.
  - Zambyte 2y ago
    > "Private" just means "their own" here. "Fork" is actually the word that means "their own". The "private" does indeed mean "proprietary" in this context.
ChocolateGod 2y ago
Doesn't Xcode ship with a closed-source build of LLVM (with patches) that you're referring to.
masklinn 2y ago
Because Apple does not direct the LLVM project, and they have their own corporate designs and plans. I'm sure they upstream what changes they think will be accepted, but there's no guarantee upstream would accept what they want or need let alone on the timeline they need it.
GeekyBear 2y ago
> Today there are a few non-trivial differences from LLVM, but we are actively working on either upstreaming or reverting those differences https://github.com/swiftlang/llvm-project https://github.com/swiftlang/llvm-project

pjmlp 2y ago

Because the same also applies to clang, and contrary to what people think, Apple like every other big tech, is only as nice to FOSS as they need to be for their own purposes. Same applies to all C and C++ compiler vendors, that have replaced their proprietary compilers (there are plenty more than just clang/gcc/msvc), with LLVM. Such is the freedom of Apache/MIT/BSD style licenses.

peppermint_gum 2y ago
Swift's LLVM fork is open-source, just not upstreamed. No Free Software license requires forks to upstream their changes. https://github.com/swiftlang/llvm-project https://github.com/swiftlang/llvm-project
- pjmlp 2y ago
  Yet you're complaining that they are using the licence exactly as they feel like.
  - nequo 2y ago
    Parent was not complaining. Parent was asking what the rationale is behind maintaining a separate LLVM fork instead of upstreaming and reducing the maintenance burden on Apple engineers.
- Zambyte 2y ago
  Referring to their fork as "private" seems quite misleading then.
okr 2y ago
I would not say its about niceness, its more about necessities. If ya don't own something, the walls are high to have anything changed, naturally. Because it might not be aligned with what the owner has had in it's mind. And you want to move quickly. So you fork and apply your changes. But i also think, in the long run, it hurts, bcs at some point, you forks are too diverged. But so is life.

ezfe 2y ago

I’ve just read the swift build guide and there’s no sign of a closed-source version of LLVM. What are you talking about?

mkl 2y ago
peppermint_gum didn't mention a closed-source version of LLVM either. "Private" just means "their own" here.
- Zambyte 2y ago
  > "Private" just means "their own" here. "Fork" is actually the word that means "their own". The "private" does indeed mean "proprietary" in this context.

ChocolateGod 2y ago

Doesn't Xcode ship with a closed-source build of LLVM (with patches) that you're referring to.

masklinn 2y ago

Because Apple does not direct the LLVM project, and they have their own corporate designs and plans. I'm sure they upstream what changes they think will be accepted, but there's no guarantee upstream would accept what they want or need let alone on the timeline they need it.

GeekyBear 2y ago

> Today there are a few non-trivial differences from LLVM, but we are actively working on either upstreaming or reverting those differences https://github.com/swiftlang/llvm-project https://github.com/swiftlang/llvm-project