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[RFA] libiberty/cplus-dem.c:demangle_template() problem?


I noticed a SIGSEGV inside GDB while reading the symbol table.
What GDB does with each symbol is try to compute their demangled
name. The SEGV occured because the compiler I used (GNAT) generated
a symbol which the demangle did not like:


GDB basically called cplus_demangle() with the above name, and kaboom!
SIGSEGV inside work_stuff_copy_to_from().

What happened is that cplus_demangle() ends up trying to demangle the
symbol using gnu_special() which tries to see if the symbol is a
template by calling demangle_template().

The value given for parameter REMEMBER is 1, so the first thing the
function does is registering a Btype inside the work_stuff structure.
But as it realizes it actually is not a template, it aborts the
execution and returns zero. However, the work->btypevec vector now
contains a NULL entry. When the code later tries to make a copy of the
work_stuff structure, if segfaults because it's trying to copy a NULL

I think the right fix is to only register the Btype when we know we
are going to store it. In the present case, the attached patch seemed
to be the right fix. I also attached a patch for the testsuite.  The
testdriver segfaults before I apply my patch, and runs to completion
after. The output is unchanged.

2003-10-19  J. Brobecker  <>

	* cplus-dem.c (demangle_template): Register a new Btype only
	when needed.
	* testsuite/demangle-expected: Add a new test.

OK to apply?


Attachment: libiberty.diff
Description: cplus-dem.c.diff

Attachment: demangle-expected.diff
Description: Text document

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