Rename function in object code

main.c

#include <stdio.h>
#include <execinfo.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>

void handler(int sig) {
	void *array[10];
	size_t size;

	// get void*'s for all entries on the stack
	size = backtrace(array, 10);

	// print out all the frames to stderr
	fprintf(stderr, "Error: signal %d:\n", sig);
	backtrace_symbols_fd(array, size, STDERR_FILENO);
	exit(1);
}

// will be renamed to v.foo
void v_foo() {
	int *foo = (int*)-1; // make a bad pointer
	printf("%d\n", *foo); // causes segfault
}

void bar() { v_foo(); }
void foo() { bar(); }

int main(int argc, char* argv[]) {
	signal(SIGSEGV, handler);   // install our handler
	foo(); // this will call foo, bar, and baz.  baz segfaults.
	return 0;
}

main.v

// gcc -g -O -c main.
// v run main.v
// gcc -g -rdynamic main.o -o main
// ./main => f_foo is v.foo in error
import os

fn main() {
	to_replace := 'v_foo'
	replace_to := 'v.foo'
	mut elf := os.read_bytes('main.o')?
	mut new_elf := []byte{}
	for i := 0; i < elf.len; i++ {
		c := elf[i]
		if c == to_replace[0] {
			mut found := true
			if i + to_replace.len > elf.len {
				break
			}
			for j in 0 .. to_replace.len {
				c2 := elf[i + j]
				cr := to_replace[j] // current character which should be replaced
				if c2 != cr {
					found = false
					break
				}
			}
			if found {
				// insert new ones
				new_elf << replace_to.bytes()
				i += to_replace.len - 1
			} else {
				new_elf << c
			}
		} else {
			new_elf << c
		}
	}
	os.write_file_array('main.o', new_elf)?
}