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Re: [PATCH] dwarf.h: Remove non-existing DW_TAG_mutable_type.
- From: Josh Stone <jistone at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Wed, 18 Jun 2014 08:48:20 -0700
- Subject: Re: [PATCH] dwarf.h: Remove non-existing DW_TAG_mutable_type.
On 06/18/2014 02:48 AM, Mark Wielaard wrote:
> The DW_TAG_mutable_type was only mentioned in an early draft of DWARFv3.
> But was removed because there are no C++ mutable qualified types. It was
> replaced by a new attribute DW_AT_mutable on DW_TAG_member DIEs. The new
> attribute is available in dwarf.h.
> http://dwarfstd.org/ShowIssue.php?issue=050223.1
>
> DW_TAG_mutable_type was only used internally in some backends (which
> just ignored it anyway). dwarves did use it to turn it into a string
> value, libabigail used it and ignored it (patches to remove sent).
> GCC, GDB and binutils don't use nor define it.
It's fine to patch its use out, in elfutils and others, but why take the
API hit of removing the constant? The number is still allocated, so it
won't do any harm to leave it there.
For example, libdwarf just commented on the removal:
> /* Do not use DW_TAG_mutable_type */
> #define DW_TAG_mutable_type 0x3e /* Withdrawn from DWARF3 by DWARF3f. */