Mull miscompiles code with jump tables (partially solved)

[AlexDenisov]

When the following code compiles:

int printf(const char *, ...);
int main(int argc, char **argv) {
  static const void *jump_table[] = {&&label, &&label2};
  goto *jump_table[argc - 1];
label:
  printf("label1\n");
  goto out;
label2:
  printf("label2\n");
  goto out;
out:
  return 0;
}

Clang generates a global jump table containing blockaddresses.

E.g.:

@main.jump_table = internal global [2 x i8*] [i8* blockaddress(@main, %11), i8* blockaddress(@main, %13)], align 16

Mull corrupts the blockaddresses when it replaces the original function with an indirect stub.

We should be also duplicating and fixing all the blockaddresses before destructive actions.

[AlexDenisov]

As a workaround, Mull does not mutate functions that have basic blocks with blockaddress taken.