C++ demangler fix

[Gary Benson <gbenson at redhat dot com>]

Hi all,

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 http://mentorembedded.github.io/cxx-abi/abi.html#mangling
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
http://sourceware.org/bugzilla/show_bug.cgi?id=14963 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

--
http://gbenson.net/

Attachment: pr14963.patch
Description: Text document