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Re: [PATCH] Allow DW_OP_GNU_uninit in dwarf_expr_require_composition
- From: Tom Tromey <tom at tromey dot com>
- To: Andreas Arnez <arnez at linux dot vnet dot ibm dot com>
- Cc: Tom Tromey <tom at tromey dot com>, gdb-patches at sourceware dot org
- Date: Mon, 10 Oct 2016 16:40:54 -0600
- Subject: Re: [PATCH] Allow DW_OP_GNU_uninit in dwarf_expr_require_composition
- Authentication-results: sourceware.org; auth=none
- References: <m3lh3zuf30.fsf@oc1027705133.ibm.com> <87lgxxctli.fsf@tromey.com> <m3a8ece6iw.fsf@oc1027705133.ibm.com>
>>>>> "Andreas" == Andreas Arnez <arnez@linux.vnet.ibm.com> writes:
Andreas> You mean to allow DW_OP_GNU_uninit to terminate any simple
Andreas> location description?
Yes.
>> That is, assuming DW_OP_GNU_uninit is useful at all.
>> Another option would be to deprecate it.
Andreas> Right, I wonder about its usefulness as well. For a variable
Andreas> with fixed location it may cover a small window where the
Andreas> compiler can be certain that the variable is uninitialized. I
Andreas> guess this *might* be useful sometimes?
Andreas> Is there even a DWARF issue for this? Or a formal
Andreas> specification?
I don't think so. Last time I looked into this all I was able to find
were the patch submissions to gcc and gdb. IIRC they weren't all that
informative though.
Tom