Re: [PATH] nios2: Fix parsing of pseudo-instructions

[Sandra Loosemore <sandra at codesourcery dot com>]

On 09/27/2017 05:18 PM, Henry Wong wrote:
> The Nios II assembler handles pseudo-instructions by "suitable fiddling
> with the operands". When a malformed pseudo-instruction is used (too few
> operands), nios2_modify_arg/nios2_negate_arg blindly modifies operands
> that may not exist, causing a segfault. This patch checks that a
> pseudo-instruction has enough operands before trying to modify them, for
> cases where it matters.

Thank you for reporting this bug.

> Changes:
>
> * config/tc-nios2.c (nios2_modify_arg, nios2_negate_arg): Fix segfault
> when parsing Nios II pseudo-instructions that have missing arguments
> * testsuite/gas/nios2/illegal_pseudoinst.s: New test for illegal Nios II
> pseudo-instructions
> * testsuite/gas/nios2/illegal_pseudoinst.l: stderr output
> * testsuite/gas/nios2/nios2.exp: Changed so the above new test is run.

Hmmm.  I think it would be better to put a more general check for the 
right number of arguments in nios2_translate_pseudo_insn; add a field to 
nios2_ps_insn_infoS to hold the expected number of arguments for the 
pseudo-op, and check it before dispatching to arg_modifier_func.

Also, your patch doesn't follow GNU coding standards with regards to 
whitespace and indentation.

Do you want to submit a revised patch, or have me handle the fix?

-Sandra