[C++ PATCH] demangler fix (take 2)

[Gary Benson <gbenson at redhat dot com>]

Hi all,

This is a resubmission of my previous demangler fix [1] rewritten
to avoid using hashtables and other libiberty features.

>From the above referenced email:

d_print_comp maintains a certain amount of scope across calls (namely
a stack of templates) which is used when evaluating references in
template argument lists.  If such a reference is later used from a
subtitution then the scope in force at the time of the substitution is
used.  This appears to be wrong (I say appears because I couldn't find
anything in the API [2] to clarify this).

The attached patch causes the demangler to capture the scope the first
time such a reference is traversed, and to use that captured scope on
subsequent traversals.  This fixes GDB PR 14963 [3] whereby a
reference is resolved against the wrong template, causing an infinite
loop and eventual stack overflow and segmentation fault.

I've added the result to the demangler test suite, but I know of no
way to check the validity of the demangled symbol other than by
inspection (and I am no expert here!)  If anybody knows a way to
check this then please let me know!  Otherwise, I hope this
not-really-checked demangled version is acceptable.

Thanks,
Gary

[1] http://gcc.gnu.org/ml/gcc-patches/2013-09/msg00215.html
[2] http://mentorembedded.github.io/cxx-abi/abi.html#mangling
[3] http://sourceware.org/bugzilla/show_bug.cgi?id=14963

-- 
http://gbenson.net/

Attachment: 14963-2.patch
Description: Text document