src/test/run-pass/drop-flag-sanity-check.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // compile-flags: -Z force-dropflag-checks=on
  12 // ignore-emscripten
  13
  14 // Quick-and-dirty test to ensure -Z force-dropflag-checks=on works as
  15 // expected. Note that the inlined drop-flag is slated for removal
  16 // (RFC 320); when that happens, the -Z flag and this test should
  17 // simply be removed.
  18 //
  19 // See also drop-flag-skip-sanity-check.rs.
  20
  21 use std::env;
  22 use std::process::Command;
  23
  24 fn main() {
  25     let args: Vec<String> = env::args().collect();
  26     if args.len() > 1 && args[1] == "test" {
  27         return test();
  28     }
  29
  30     let mut p = Command::new(&args[0]).arg("test").spawn().unwrap();
  31     // The invocation should fail due to the drop-flag sanity check.
  32     assert!(!p.wait().unwrap().success());
  33 }
  34
  35 #[derive(Debug)]
  36 struct Corrupted {
  37     x: u8
  38 }
  39
  40 impl Drop for Corrupted {
  41     fn drop(&mut self) { println!("dropping"); }
  42 }
  43
  44 fn test() {
  45     {
  46         let mut c1 = Corrupted { x: 1 };
  47         let mut c2 = Corrupted { x: 2 };
  48         unsafe {
  49             let p1 = &mut c1 as *mut Corrupted as *mut u8;
  50             let p2 = &mut c2 as *mut Corrupted as *mut u8;
  51             for i in 0..std::mem::size_of::<Corrupted>() {
  52                 // corrupt everything, *including the drop flag.
  53                 //
  54                 // (We corrupt via two different means to safeguard
  55                 // against the hypothetical assignment of the
  56                 // dtor_needed/dtor_done values to v and v+k.  that
  57                 // happen to match with one of the corruption values
  58                 // below.)
  59                 *p1.offset(i as isize) += 2;
  60                 *p2.offset(i as isize) += 3;
  61             }
  62         }
  63         // Here, at the end of the scope of `c1` and `c2`, the
  64         // drop-glue should detect the corruption of (at least one of)
  65         // the drop-flags.
  66     }
  67     println!("We should never get here.");
  68 }