// stackpointer.c
//
// gcc -shared -fpic -o stackpointer.dylib stackpointer.c
//
// import ctypes
// sp = ctypes.CDLL('./stackpointer.dylib')
// address = sp.get_machine_stack_pointer()

#include <stdint.h>

uintptr_t get_machine_stack_pointer(void)
{
    return (uintptr_t)__builtin_frame_address(0);
}

# recursion_limit_test.py
import sys
import ctypes
import ctypes.util

# Obtain stack address and stack size as reported by non-portable pthread functions:
libc = ctypes.CDLL(ctypes.util.find_library('c'))

libc.pthread_self.restype = ctypes.c_void_p

libc.pthread_get_stackaddr_np.argtypes = [ctypes.c_void_p]
libc.pthread_get_stackaddr_np.restype = ctypes.c_void_p

libc.pthread_get_stacksize_np.argtypes = [ctypes.c_void_p]
libc.pthread_get_stacksize_np.restype = ctypes.c_ulonglong

this_thread = libc.pthread_self()

stack_address = libc.pthread_get_stackaddr_np(this_thread)
stack_size = libc.pthread_get_stacksize_np(this_thread)

print(f"Stack address: {stack_address} = 0x{stack_address:X}")
print(f"Stack size: {stack_size} = {stack_size / 1024.0} kB = {stack_size / 1024**2} MB")

# Helper for tracking stack pointer location
splib = ctypes.CDLL('./stackpointer.dylib')
splib.get_machine_stack_pointer.restype = ctypes.c_void_p
stack_pointer = splib.get_machine_stack_pointer()
print(f"Stack pointer: 0x{stack_pointer:X}, depth: {(stack_address - stack_pointer)/1024:.2f} kB")

# Recursion limit test
limit = sys.getrecursionlimit()
counter = 0

class A:
    def __getattribute__(self, name):
        global counter
        counter += 1
        stack_pointer = splib.get_machine_stack_pointer()
        print(f"Recursion level: {counter}, stack pointer: 0x{stack_pointer:X}, depth: {(stack_address - stack_pointer)/1024:.2f} kB")

        # Increase recursion limit, if necessary
        global limit
        if counter + 1 >= limit:
            limit *= 2
            print(f"Increasing recursion limit: {limit}")
            sys.setrecursionlimit(limit)

        # Recurse
        return getattr(self, name)


a = A()
print("Testing Recursion Limit")
print(f"Initial limit: {limit}")
try:
    a.test
except RecursionError:
    print(f"Recursion Limit ok (reached level {counter})")

% python3.13 recursion_limit_test.py
Stack address: 6101024768 = 0x16BA64000
Stack size: 16777216 = 16384.0 kB = 16.0 MB
Stack pointer: 0x16BA622A0, depth: 7.34 kB
Testing Recursion Limit
Initial limit: 1000
Recursion level: 1, stack pointer: 0x16BA61CD0, depth: 8.80 kB
Recursion level: 2, stack pointer: 0x16BA616A0, depth: 10.34 kB
Recursion level: 3, stack pointer: 0x16BA610B0, depth: 11.83 kB
...
Recursion level: 4997, stack pointer: 0x16B323CD0, depth: 7424.80 kB
Recursion level: 4998, stack pointer: 0x16B3236E0, depth: 7426.28 kB
Recursion Limit ok (reached level 4999)

% python3.14 recursion_limit_test.py
Stack address: 6091063296 = 0x16B0E4000
Stack size: 16777216 = 16384.0 kB = 16.0 MB
Stack pointer: 0x16B0E1CC0, depth: 8.81 kB
Testing Recursion Limit
Initial limit: 1000
Recursion level: 1, stack pointer: 0x16B0E1120, depth: 11.72 kB
Recursion level: 2, stack pointer: 0x16B0E0550, depth: 14.67 kB
...
Recursion level: 1320, stack pointer: 0x16AD13470, depth: 3906.89 kB
Recursion level: 1321, stack pointer: 0x16AD128A0, depth: 3909.84 kB
Recursion Limit ok (reached level 1322)