[ARM] Avoid dereferencing null pointers

[Alan Modra]

On Tue, Oct 23, 2018 at 04:21:41PM +0200, Christophe Lyon wrote:
> Hi,
> 
> While building an ARM FDPIC toolchain with a compiler generating Thumb
> code, I face a couple of null pointer dereferences in cmse_scan().
> 
> When browsing ld-uClibc.so.1, all the external symbols have no info in
> sym_hashes (sym_hashes[X] == NULL), and when handling libgcc_s.so.1
> for the 2nd time in the same command, sym_hashes == NULL.
> 
> I don't know why this doesn't happen with a compiler generating Arm
> code (ie. why the symbol tables are handled differently), but the
> attached small patch prevents the linker from crashing.
> 
> OK?

No, this is just papering over the real problem.  You need to find out
why the sym hashes are not being set up (or are being overwritten).

-- 
Alan Modra
Australia Development Lab, IBM