get_sp.c

#include "get_sp.h"

void *get_sp(void) {
  return __builtin_frame_address(1);
}

get_sp.h

#ifndef get_sp_h
#define get_sp_h

extern void *get_sp(void);

#endif /* get_sp_h */

Infinite_Loop.swift

import Darwin

class FooObject {
  func foo() {
    print(self)
    foo_2()
  }
}

func foo_2() {
  let fooObject: FooObject = get_sp().load(fromByteOffset: -0x10, as: FooObject.self)

  // void *buffer[2] (Heap)
  let buffer: UnsafeMutableBufferPointer<UnsafeMutableRawPointer?> = .allocate(capacity: 2)

  let count: Int32 = backtrace(buffer.baseAddress, 2)
  assert(count == 2)

  var info: Dl_info = .init()
  dladdr(buffer[1], &info)
  buffer.deallocate()

  typealias FooType = @convention(c) (UnsafeRawPointer) -> Void
  
  let foo = unsafeBitCast(info.dli_saddr, to: FooType.self)

  foo(Unmanaged.passUnretained(fooObject).toOpaque())
}

FooObject().foo()