Cause of the ?? in backtrace

[Rich Rattanni]

In order to ensure the library has debug info built into it, do you
just need to build the library with the -g option specified during
compilation?  Or is it more involved?

On 3/12/07, Michael Snyder <Michael.Snyder@palmsource.com> wrote:
> On Mon, 2007-03-12 at 10:47 -0400, Rich Rattanni wrote:
> > Why would one get the following when trying to do a backtrace in GDB...
> > (gdb) bt
> > #0  0x403cdcb4 in _int_malloc () from /lib/libc.so.6
> > #1  0x403cedfc in malloc () from /lib/libc.so.6
> > #2  0x401c4418 in sqlite3MallocRaw () from /usr/lib/libsqlite3.so.0
> > #3  0x401c450c in sqlite3StrNDup () from /usr/lib/libsqlite3.so.0
> > #4  0x401cc070 in sqlite3VdbeChangeP3 () from /usr/lib/libsqlite3.so.0
> > #5  0x401cc0ac in sqlite3VdbeOp3 () from /usr/lib/libsqlite3.so.0
> > #6  0x401ac010 in sqlite3CodeSubselect () from /usr/lib/libsqlite3.so.0
> > #7  0x401ab4b0 in sqlite3ExprCode () from /usr/lib/libsqlite3.so.0
> > #8  0x401abd00 in sqlite3ExprIfFalse () from /usr/lib/libsqlite3.so.0
> > #9  0x401d02cc in sqlite3WhereBegin () from /usr/lib/libsqlite3.so.0
> > #10 0x401bf13c in sqlite3Select () from /usr/lib/libsqlite3.so.0
> > #11 0x401b6978 in sqlite3Parser () from /usr/lib/libsqlite3.so.0
> > #12 0x401c12e0 in sqlite3RunParser () from /usr/lib/libsqlite3.so.0
> > #13 0x47de97e0 in ?? ()        <------------------------------- This
> > is my problem
>
>
> Specifically, the ?? means that gdb could not find a symbol to
> correspond with the instruction address 0x47de97e0.  This might
> mean any number of things.
>
> If the address is legitimate (ie. the return address of sqlite3RunParser
> really does point back to a caller at 0x47de97e0), then this caller
> may be from a library for which gdb has no symbols.  It might be
> self-generating code, in which case it may never have had any
> symbols.
>
> Or the address may NOT be legitimate, and may have come about
> as a result of a corrupted stack or something.
>
>