`cdd_done()` generates heap-use-after-free error for "CDD timed predecessor static test"

[magoorden]

From #31.

I noticed that I did not deinitialized the CDD library in the new test case. So I added in my code locally that

TEST_CASE("CDD timed predecessor static test")
{
 ...
 cdd expected = cdd_remove_negative(expected1 | expected2);

  REQUIRE(cdd_equiv(result, expected));
  cdd_done();
}

But now I get an unexpected 'heap-use-after-free' error from AddressSanitizer. It has something to do with cdd_remove_negative, since when I remove that one from the shown line above, the error is no longer present.

The full error description is

==10537==ERROR: AddressSanitizer: heap-use-after-free on address 0x7fb6edb73800 at pc 0x55d1e3892d5b bp 0x7ffd7b9d57f0 sp 0x7ffd7b9d57e0
WRITE of size 8 at 0x7fb6edb73800 thread T0
    #0 0x55d1e3892d5a in cdd_rec_deref /home/martijn/Documents/UCDD/src/kernel.c:439
    #1 0x55d1e3879e0b in cdd::~cdd() /home/martijn/Documents/UCDD/src/cppext.cpp:44
    #2 0x55d1e3822e06 in DOCTEST_ANON_FUNC_7 /home/martijn/Documents/UCDD/test/test_cdd.cpp:932
    #3 0x55d1e37ee076 in doctest::Context::run() /home/martijn/Documents/UCDD/libs/doctest/include/doctest/doctest.h:6727
    #4 0x55d1e37efe6e in main /home/martijn/Documents/UCDD/libs/doctest/include/doctest/doctest.h:6805
    #5 0x7fb6f123b082 in __libc_start_main ../csu/libc-start.c:308
    #6 0x55d1e37b76dd in _start (/home/martijn/Documents/UCDD/cmake-build-debug/test/test_cdd+0x1c6dd)

0x7fb6edb73800 is located 0 bytes inside of 160000-byte region [0x7fb6edb73800,0x7fb6edb9a900)
freed by thread T0 here:
    #0 0x7fb6f186240f in __interceptor_free ../../../../src/libsanitizer/asan/asan_malloc_linux.cc:122
    #1 0x55d1e3891f59 in cdd_done /home/martijn/Documents/UCDD/src/kernel.c:286
    #2 0x55d1e3822dfa in DOCTEST_ANON_FUNC_7 /home/martijn/Documents/UCDD/test/test_cdd.cpp:937
    #3 0x55d1e37ee076 in doctest::Context::run() /home/martijn/Documents/UCDD/libs/doctest/include/doctest/doctest.h:6727
    #4 0x55d1e37efe6e in main /home/martijn/Documents/UCDD/libs/doctest/include/doctest/doctest.h:6805
    #5 0x7fb6f123b082 in __libc_start_main ../csu/libc-start.c:308

previously allocated by thread T0 here:
    #0 0x7fb6f1862808 in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cc:144
    #1 0x55d1e38919a1 in cdd_init /home/martijn/Documents/UCDD/src/kernel.c:197
    #2 0x55d1e3821afe in DOCTEST_ANON_FUNC_7 /home/martijn/Documents/UCDD/test/test_cdd.cpp:891
    #3 0x55d1e37ee076 in doctest::Context::run() /home/martijn/Documents/UCDD/libs/doctest/include/doctest/doctest.h:6727
    #4 0x55d1e37efe6e in main /home/martijn/Documents/UCDD/libs/doctest/include/doctest/doctest.h:6805
    #5 0x7fb6f123b082 in __libc_start_main ../csu/libc-start.c:308

---

I guess that cdd_done() frees all cdd instances, but then you have one expected left, which results in double-free. Try putting your expected into a separate scope instead, like:

  {  
     cdd expected = cdd_remove_negative(expected1 | expected2);
     REQUIRE(cdd_equiv(result, expected));
  }
  cdd_done();

This will guarantee that expected is destroyed before cdd_done(). I am not entirely sure why cdd_done() is needed, looks like another hack with global variables :-(

---

Doing this will push the error message further back into the test case. It only works when I do

TEST_CASE("CDD timed predecessor static test")
{
    cdd_init(100000, 10000, 10000);
    cdd_add_clocks(4);
    cdd_add_bddvar(3);
    {
      // Actual content of the test case.
    }
    cdd_done();
}

This is not what I expected of using cdd_done(), see other test cases (like "CDD intersection with size 3") where there is no need for putting the content of the test case within a name space.