Doc building for ios

This currently does not work.

Options

Option 1: Convert Rust's LLVM bitcode to C-code

rustc foo.rs -o foo.stage2 -O --save-temps
llc -march=c foo.bc -o foo.c

Option 2: Use Rust's Android-ARM assembler code

TODO: something using rustc --emit-llvm -S --target=arm-linux-androideabi

Option 3: Add native iOS-support to Rust

1. Adjust src/rt/rust_builtin.cpp:

#ifdef __APPLE__
    #include <TargetConditionals.h>
    #include <mach/mach_time.h>

    #if defined(TARGET_OS_IPHONE)
        extern char **environ;
    #else
        #include <crt_externs.h>
    #endif
#endif

and

rust_env_pairs() {
#ifdef __APPLE__ && !defined(TARGET_OS_IPHONE)
    char **environ = *_NSGetEnviron();
#endif

1. Adjust src/rt/arch/arm/_context.S:

#if defined(__APPLE__)
.align 2
#else
.align
#endif

1. Adjust src/rt/arch/arm/record_sp.S:

#if defined(__APPLE__)
.align 2
#else
.align
#endif

1. Build Rust:

mkdir build; cd build
../configure --target-triples=arm-apple-darwin
make VERBOSE=1

1. Use Rust:

rustc --target=arm-apple-darwin foo.rs

TODO

• Compilation currently fails in libuv, see #10249.

Possible adjustments

• Compilation:
  • Compile twice, with both -arch armv7 and -arch armv7s (A6 processor) ?
    • See https://github.com/ghc-ios/ghc-ios-scripts/blob/master/arm-apple-darwin10-gcc
• Code:
  • src/librustc/back/arm.rs
  • src/rt/arch/arm/record_sp.S

Resources

• https://github.com/mozilla/rust/issues/6170
• ARM Machine Directives: .align
• Building a GHC cross-compiler for Apple iOS targets
• Doc building for android
• environ.7: _NSGetEnviron()
• iOS ABI Function Call Guide
• llc
• llvm-dis
• Note seeing LLVM output from rust