[Pixman] pixman on iOS

[Søren Sandmann]

Jeremy Huddleston <jeremyhu at apple.com> writes:

> Can you give me a bit more specifics?  Do you have a reduced test case
> that you can show me of the problems you are having?  Have you opened
> a bug report on llvm's bugzilla?  Have you filed a radar with Apple's
> bug tracker?

As I understand it:

The reduced test case is to just run the configure script on iOS. It
will produce something like this:

  Checker whether to use ARM NEON assembler ... ARM NEON intrinsics not detected

Which is a problem because pixman has an extensive set of high-quality
NEON fast paths that signifcantly improves performance when NEON is
available.

It's not easy to solve this problem because the issue is that the
toolchain used for iOS simply can't cope with the assembler directives
used in pixman-arm-neon-asm.S. Hence people have resorted to compiling
it on Linux and then using a disassembler to get preprocessed assembly
back that the iOS toolchain *can* cope with.

I geuss the remark I made in the release announcement was a bit
misleading: it's not too difficult to build pixman itself; it's building
the NEON optimizations that is difficult.


Søren