[Bug demangler/79099] New: Memory leak in cplus-dem.c:2232

[ppluzhnikov at google dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79099

            Bug ID: 79099
           Summary: Memory leak in cplus-dem.c:2232
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: demangler
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ppluzhnikov at google dot com
  Target Milestone: ---

Discovered with LLVM libFuzzer (http://llvm.org/docs/LibFuzzer.html).

Using current binutils trunk (libiberty is identical to r244484):

valgrind --leak-check=full build/binutils/cxxfilt
__ELztype_31__tp__H1f_H1f0U_F0U_Fv__F__ELztype_31__tp__H1f0U_FS

 (signed) __ELztype_31__tp__H1f_H1f0U_F0U_Fv__F__ELztype_31__tp<0>(void)

==24094== HEAP SUMMARY:
==24094==     in use at exit: 9 bytes in 2 blocks
==24094==   total heap usage: 33 allocs, 31 frees, 888 bytes allocated
==24094==
==24094== 9 (8 direct, 1 indirect) bytes in 1 blocks are definitely lost in
loss record 2 of 2
==24094==    at 0x40307C4: malloc
(valgrind/coregrind/m_replacemalloc/vg_replace_malloc.c:270)
==24094==    by 0x7D1157: xmalloc
(/build/libiberty/../../libiberty/xmalloc.c:147)
==24094==    by 0x7BD245: demangle_template
(/build/libiberty/../../libiberty/cplus-dem.c:2232)
==24094==    by 0x7C05E5: demangle_signature
(/build/libiberty/../../libiberty/cplus-dem.c:1695)
==24094==    by 0x7C0994: iterate_demangle_function
(/build/libiberty/../../libiberty/cplus-dem.c:2747)
==24094==    by 0x7C1598: internal_cplus_demangle
(/build/libiberty/../../libiberty/cplus-dem.c:2975)
==24094==    by 0x7BC491: cplus_demangle
(/build/libiberty/../../libiberty/cplus-dem.c:922)
==24094==    by 0x405643: demangle_it
(/build/binutils/../../binutils/cxxfilt.c:62)
==24094==    by 0x40525B: main (/build/binutils/../../binutils/cxxfilt.c:227)
==24094==
==24094== LEAK SUMMARY:
==24094==    definitely lost: 8 bytes in 1 blocks
==24094==    indirectly lost: 1 bytes in 1 blocks
==24094==      possibly lost: 0 bytes in 0 blocks
==24094==    still reachable: 0 bytes in 0 blocks
==24094==         suppressed: 0 bytes in 0 blocks


The same leak was definitely present as early as 2016/10/09.
The version of binutils imported from head on 2016/06/09 does not appear to
have this leak.