output.txt

⏿ c++11 recompile-a-function.cpp -ltcc ; and ./a.out
need 127 bytes.
relocating to 7fcefd403b90
foo(0) = 0
foo(1) = 1
foo(2) = 2
foo(3) = 3
foo(4) = 4
foo(5) = 5
foo(6) = 6
foo(7) = 7
foo(8) = 8
foo(9) = 9
<string>: error: 'foo' defined twice
Assertion failed: (-1 != tcc_compile_string(instance, "char foo(int t) { return t; }")), function main, file recompile-a-function.cpp, line 24.

recompile-function.cpp

#include <iostream>
using std::cout;
using std::endl;

#include "libtcc.h"

int main(int argc, char* argv[]) {
  TCCState* instance = tcc_new();
  tcc_set_output_type(instance, TCC_OUTPUT_MEMORY);
  assert(-1 != tcc_compile_string(instance, "char foo(int t) { return t; }"));

  int size;
  assert(-1 != (size = tcc_relocate(instance, NULL)));
  char* memory = new char[size];
  printf("need %d bytes.\n", size);
  printf("relocating to %llx\n", (unsigned long long)memory);

  assert(-1 != tcc_relocate(instance, (void*)memory));
  
  // tcc_delete(instance); // uncomment this line to crash on macOS
  //
  // deleting the tcc instance here on macOS leads to a crash later,
  // then foo is called.
  //
  
  char (*foo)(int) = (char (*)(int))tcc_get_symbol(instance, "foo");
  for (int t = 0; t < 10; t++) {
    printf("foo(%d) = %d\n", foo(t), t);
  }

  // even after a relocate, we may not recompile foo
  // <string>: error: 'foo' defined twice
  assert(-1 != tcc_compile_string(instance, "char foo(int t) { return t; }"));

  tcc_delete(instance);
  return 0;
}