JIT with mulle clang

JIT compilation should be easy, if you have the proper mulle-objc-runtime.h header accessible. Your JIT code should import it, which it usually does by virtue of including Foundation.h, MulleObjC.h or some such header.

The resulting compiled object will contain a function __load_mulle_objc that is an __attribute__(( constructor)) function, meaning that it should execute as soon as loaded.

Depending on the JIT setup you may have to call __load_mulle_objc yourself, to get classes, categories, strings, selectors etc. added to the runtime.

Compiling without mulle-objc-runtime.h

The lldb debugger does some funky JIT stuff, as the mulle-objc-runtime.h header is not readily available. To support such scenarios, your code must define a top level variable __mulle_objc_objccompilerinfo like so:

static const 
struct mulle_clang_objccompilerinfo
{
  unsigned int   load_version;
  unsigned int   runtime_version;
} __mulle_objc_objccompilerinfo =
{
  12, // load version must match!
      // check with: mulle-clang --version
  0   // 0 to not emit __load_mulle_objc 
      // otherwise provide the current runtime version
      // as: ((0 << 20) | (13 << 8) | 1) for 0.13.1
};